Instrument cluster including telltale illumination

ABSTRACT

An instrumentation gauge for a vehicle includes a single piece light guide divided into multiple sections by an opaque light guide insert. The single piece light guide includes at least one telltale graphic printed on a surface of the light guide in each of the light guide sections. When light is communicated into a given section of the light guide, the light scatters on the telltale graphic causing the graphic to be illuminated and distinguishable from a same or similar colored background.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.14/261,954 filed on Apr. 25, 2014 and is incorporated herein byreference.

TECHNICAL FIELD

The present disclosure relates generally to instrument clusters for avehicle, and more specifically to a method and apparatus forilluminating telltales on an instrument cluster.

BACKGROUND

Instrument clusters for a vehicle are typically located on a vehicledashboard and may include a speedometer, tachometer, engine conditionindicator, ABS braking indicator, and other vehicle marks. This clusterof display marks may have lighting to illuminate each mark, whenappropriate. For example, an ABS braking mark may be illuminated whenthe vehicle is undergoing ABS braking. In previous designs, thislighting was provided by individual lamps or LEDs that illuminate eachindicator of the dashboard. The type of lighting used in these designstakes up significant space and can require a high voltage circuit tosupply current to each of the lamps. A high voltage further requiresinsulation to protect against shock, thereby increasing the cost andsize of the instrument cluster.

One alternative to the lamp illumination described above is the use ofoptical light guides to bring illumination to each of the display marksof the instrument cluster. However, in order to illuminate each markindividually, each mark requires its own light guide and light source. Atypical example instrument cluster can have a significant number ofseparate indicators that require such lighting. Each light guideassociated with each indicator is painstakingly assembled into thecluster one at a time. Consequently, the use of individual light guidesrequires a great deal of time and effort for assembly in the instrumentcluster.

SUMMARY OF THE INVENTION

Disclosed is an instrumentation gauge for a vehicle including a lightguide having a plurality of light guide connections, wherein each ofsaid light guide connections is in communication with at least one of aplurality of first light sources, and wherein the light guide comprisesa single piece, a dial disposed adjacent a first surface of said lightguide, wherein said dial comprises an opaque portion, and at least onetransparent portion, at least one telltale printed on a first surface ofsaid light guide, wherein said telltale is printed in a color matching acolor of said dial, and a lighthousing for communicating light from atleast one second light source to said at least one transparent portionof said dial.

Also disclosed is a method of for illuminating a telltale in aninstrument cluster including providing a single piece light guide havinga plurality of sections, communicating light from a light source to oneof said plurality of sections through a light guide leg, and scatteringlight in all directions at a telltale graphic, wherein the telltalegraphic is printed on a surface of said light guide, therebyilluminating said telltale graphic.

Also disclosed is a light guide for an instrumentation gauge including afirst surface facing a first direction, a second surface facing a seconddirection opposite said first direction, an opaque light guide insertdividing said first surface and said second surface into a plurality oflight guide sections, at least one light guide leg extending from eachof said light guide sections, wherein said light guide leg is operableto couple said light section with a light source disposed adjacent saidlight guide leg, and wherein each of said sections comprises a telltalegraphic printed on said second surface within said section.

These and other features of the present invention can be best understoodfrom the following specification and drawings, the following of which isa brief description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates an instrument cluster for a vehicle.

FIG. 2 schematically illustrates an instrumentation gauge for theinstrument cluster of FIG. 1.

FIG. 3 schematically illustrates an exploded view of the instrumentationgauge of FIG. 2.

FIG. 4 schematically illustrates a cross section of the instrumentationgauge of FIG. 3.

FIG. 5 schematically illustrates a light guide component of aninstrumentation gauge.

FIG. 6 schematically illustrates a cross section of the light guidecomponent of an instrumentation gauge.

FIG. 7 schematically illustrates a cross section of an alternative lightguide component to the light guide component of an instrumentationgauge.

DETAILED DESCRIPTION OF AN EMBODIMENT

FIG. 1 schematically illustrates an instrument cluster 10 for a vehicle.The instrument cluster 10, include standard gauges 20, 30, each of whichindicates relevant vehicle operation information to a vehicle operatorwhile the vehicle is being used. Also included in the instrument cluster10 is an instrumentation gauge 40 that includes a light guide 42 and apointer 44. The pointer 44 is controlled by a stepper motor in astandard automotive gauge configuration.

In the illustrated example, the light guide 42 includes a circular facefacing the vehicle operator and a second circular face facing away fromthe vehicle operator, into the instrument cluster. Disposed about aradially outward edge of the light guide 42 are multiple light guidelegs 46. Each light guide leg is arranged such that the leg 46 is incommunication with a light source, such as an LED, inside the instrumentcluster 10.

The light guide 42 is split into multiple sections 48 by an opaque lightguide insert 50. The light guide insert 50 constrains light communicatedthrough the legs 46 to a section 48 of the light guide 42 correspondingto the leg 46. In some examples, the light guide insert 50 is moldedinto the light guide 42 such that the light guide 42 and the light guideinsert 50 form a singular component. One such molding technique is a twoshot molding process. In alternate examples, the light guide insert 50can be slotted into a corresponding slot, or void, in the light guide 42as a separate component.

A dial is disposed behind the light guide 42. The dial is majorityopaque, with white or color translucent graphics. In the illustratedexample of FIG. 1, the white or color translucent graphics are numbers,although alternative graphics could be utilized in place of theillustrated numbers depending on the application of the instrumentationgauge 40. When operating during low light conditions, or any otherconditions where the instrumentation gauge 40 should be illuminated, atleast one light source is lit behind the dial. As the graphics aretranslucent with the remainder of the dial being opaque, light onlypasses through the graphics, thereby illuminating the graphics.

The light guide 42 further includes one or more instrumentationtelltales 52 printed on the light guide surface facing away from thevehicle operator (toward the instrument cluster 10). The instrumentationtelltales 52 are printed in a color close to, or matching, the color ofthe opaque portion of the dial. Due to the close color matching betweenthe telltales 52 and the dial, when no light is entering the light guide42 through the legs 46, the telltales 52 blend into the dial and areeither not visible or are barely visible.

When a vehicle controller, or other vehicle component, determines thatone of the telltales 52 should be illuminated, thereby conveyinginformation to the vehicle operator, a light source in communicationwith the corresponding leg 46 is illuminated, causing the light guide totransmit light to the corresponding section 48. Due to the nature oflight guides, light waves passing through the light guide 42 is directedin a single direction and is not visible to the vehicle operator untilit exits the light guide 42. When the light waves encounter a telltale52, printed on the light guide 42, the light is scattered in everydirection. As a result of the light scattering, light is transmitted outof the light guide 42 and toward the operator. This illuminates thetelltale 52 without illuminating the remainder of the section 48 or thedial behind the light guide 42.

With continued reference to FIG. 1, FIG. 2 schematically illustrates atelltale illumination instrumentation gauge 40 isolated from theinstrumentation cluster 10, of FIG. 1. The illustrated telltaleilluminating instrumentation gauge 40 includes the features describedabove with regard to the instrumentation gauge 40 of FIG. 1.Additionally visible in the example of FIG. 2 is a lighthousing 160. Thelighthousing 160 separates light from the light sources illuminating thegraphics on the dial from the light sources illuminating each of thelegs 146. The lighthousing 160 further maintains the instrumentationgauge 140 assembly and holds each of the components in place.

With continued reference to FIGS. 1 and 2, and with like numeralsindicating like elements, FIG. 3 illustrates an exploded view of theinstrumentation gauge 140 of FIG. 2. Similarly, FIG. 4 illustrates across sectional view of an assembled instrumentation gauge 140. Asdescribed above, a dial 170 is disposed adjacent the light guide 142.The dial 170 includes graphics 172 that function in conjunction with apointer 44 (FIG. 1) that is controlled by a stepper motor (notpictured). Both the dial 170 and the light guide 142 are maintained inposition relative to each other via a lighthousing 160. A circuit board180 including light sources 182, 184 and circuitry to provide power tothe light sources 182, 184 is positioned on an opposite end of thelighthousing 160, relative to the light guide 142.

The lighthousing 160 includes an interior wall 162 and an exterior wall164. The interior wall 162 supports the dial 170 and the light guide 142in an axial direction, while the exterior wall 164 provides a radialconstraint on the light guide 142 and the dial 170. The exterior wall164 further includes notches 166 for receiving the legs 146 of the lightguide 142.

Defined between the interior wall 162 and the exterior wall 164 is a gapthat allows transmission from a first set of light sources 184 to thegraphics 172 on the dial 170. The lighthousing 160 is constructed of anopaque material, thereby preventing light from the first set of lightsources 184 from escaping. A second set of light sources 182 is disposedradially outward of the first set of light sources 184 on the circuitboards 180. The second set of light sources 182 corresponds to the legs146, with a single light source 182 corresponding to each of the legs146. In alternate examples, multiple light sources 182 can correspond toeach leg 146.

With continued reference to FIGS. 1-3, FIG. 4 illustrates a light guide300 for use in an instrumentation gauge, such as the instrumentationgauges 40, 140 illustrated in FIGS. 1-3. The example light guide 300 isconstructed of a clear material as a single piece. The single piececonstruction includes each of the legs 346. An insert slot 390 is formedin the light guide 300 for receiving the opaque lightguide insert 50(illustrated in FIG. 1).

Multiple telltale graphics 352 are printed on one face of the lightguide 300. Each of the telltale graphics 352 is positioned in onesection, such that when a given section is illuminated, only thecorresponding telltale graphic 352 is illuminated. Operation of thelight guide sections is described below with regards to FIG. 6.

Each of the telltale graphics 352 is printed in a color that blends inwith, or matches, the color of the opaque portion of the dial 172 (SeeFIGS. 3 and 4) when the section is not illuminated. In some examples,when the section is illuminated, the light reflected off the printedtelltales alters the perceived color of the telltale, thereby allow thevehicle operator to easily distinguish the telltale from the backgroundprovided by the opaque portion of the dial 170. In other examples, thereflected light does not affect the color of the illuminated portion. Inthis way, the operator is aware of the illumination of the telltale, andthe underlying message about the operational status of the vehicle.

FIG. 6 schematically illustrates a cross sectional view of an examplelight guide 500, with certain features exaggerated for explanatoryeffect. The light guide 500 includes multiple leg portions 510, each ofwhich has an end face 512 facing a corresponding light source 520. Whenlight is emitted from the light source 520, the light travels throughthe leg 510 and encounters a coupling region 530. The bend portionincludes a curvature that is designed to couple light from the lightsource 520 with the horizontal portion 560 of the light guide 500. Theparticular curvature can be decided by one of skill in the art basedupon practical considerations for the use and housing of the light guide500.

In alternative examples, the coupling region 530 can be replaced with anangled surface, such as a forty-five degree angle (relative to adirection of light from the light source 520). In example systems wherethe coupling region 530 is significantly larger than a width 562 of thelight guide 500, the illustrated coupling region 530 is ideal. In thealternative situation, where the bend portion 530 is not significantlylarger than the width 562, a single angled surface is more ideallysuited to the design.

In either example, the coupling region 530 couples the light from thelight source 520 to the horizontal portion 560. Printed on an underside554 of the horizontal portion 560 of the light guide 500 is a telltale540. In an assembled instrumentation gauge 40 (FIG. 1), the underside554 is the disc face of the light guide that is facing away from theobserver and into the instrument cluster 10.

When the light being directed by the light guide 500 contacts theprinted telltale 540, the light is scattered in every direction, asillustrated by the arrows 542. At least a portion of the light isscattered perpendicular, or approximately perpendicular to the printedtelltale 540 and is directed toward the observer. The perpendicular orapproximately perpendicular light can be observed by the observercausing the telltale 540 to appear illuminated. The non-scattered lightremains within the light guide, and is not visible to the observer. In apractical system, a portion of the light being communicated through thelight guide will leak out the outer face 552 and the inner face 554 ofthe horizontal segment 550. The leaked light is at a substantially lowangle and will not be directed toward the observer. As a result, thedial placed adjacent the underside surface 554 is not illuminated, evenwhen the telltale 540 is illuminated.

With continued reference to FIGS. 1-6, and with like numerals indicatinglike elements, FIG. 7 illustrates an alternative example light guide600, with certain features exaggerated for explanatory effect. The lightguide 600 includes multiple leg portions 610, each of which has an endface 612 facing a corresponding light source 620. When light is emittedfrom the light source 620, the light travels through the leg 610 andencounters a coupling region 630. The coupling region 630 includes acurvature that is designed to couple light from the light source 620with a horizontal portion 660 of the light guide 600. The particularcurvature can be decided by one of skill in the art based upon practicalconsiderations for the use and housing of the light guide 500. As withthe example of FIG. 6, in alternative examples the curvature of thecoupling region 630 can be replaced with an angled surface.

The coupling region 630 couples the light from the light source 5620 tothe horizontal portion 660. Printed on an underside 654 of thehorizontal portion 660 of the light guide 600 is a telltale 640. In anassembled instrumentation gauge 40 (FIG. 1), the underside 654 is thedisc face of the light guide that is facing away from the observer andinto the instrument cluster 10.

In contrast to the horizontal portion 560 of FIG. 6, the horizontalportion 660 of FIG. 7 is angled, with the outer surface 652 and theinner surface 654 not being parallel to each other. As a result of thenon-parallel surfaces 652, 654, the telltale 640 will appear skewed, orotherwise misaligned if the angles are not compensated for. The telltale640 can be printed with a stretched or skewed perspective to counteractthe angled surfaces, resulting in a non-skewed appearance.

While the above examples are described with regards to a circularinstrumentation gauge and light guide, one of skill in the art willunderstand that the above principles can be equally applied to alternateshapes such as rectangles, triangles, and the like, without impactingthe operation of the instrumentation gauge.

It is further understood that any of the above described concepts can beused alone or in combination with any or all of the other abovedescribed concepts. Although an embodiment of this invention has beendisclosed, a worker of ordinary skill in this art would recognize thatcertain modifications would come within the scope of this invention. Forthat reason, the following claims should be studied to determine thetrue scope and content of this invention.

1. A method of for illuminating a telltale in an instrument clustercomprising: providing a light guide having a plurality of sections;communicating light from a light source to one of said plurality ofsections through a light guide leg; and scattering light in alldirections at a telltale graphic, wherein the telltale graphic isprinted on a surface of said light guide, thereby illuminating saidtelltale graphic.
 2. The method of claim 1, wherein providing a lightguide having a plurality of sections further comprises dividing saidlight guide into a plurality of section by inserting an opaque lightguide insert into a receiving slot of said light guide.
 3. The method ofclaim 1, wherein providing a light guide having a plurality of sectionsfurther comprises dividing said light guide into a plurality of sectionby including an opaque insert portion integral to said light guide. 4.The method of claim 1, wherein communicating light from a light sourceto one of said plurality of sections through a light guide leg comprisesilluminating said light source, allowing light from said light source toenter a light guide connection, and reflecting light from said lightguide connection to face portion of said light guide, thereby providinglight to said face portion of said light guide.
 5. The method of claim4, wherein reflecting light from said light guide connection to the faceportion of said light guide comprises coupling the light guideconnection to a corresponding face portion using a coupling region, andwherein said coupling region comprises at least one of an angled surfaceand a curvature.
 6. The method of claim 1, wherein scattering light inall directions at a telltale graphic comprises illuminating saidtelltale while simultaneously not illuminating a dial adjacent saidlight guide, thereby differentiating said telltale from said dial. 7.The method of claim 6, wherein said telltale graphic and said dial areat least approximately the same color.
 8. The method of claim 1, whereinproviding the light guide housing the plurality of sections comprisesproviding a single piece light guide.
 9. A method for constructing alight guide for an instrument cluster comprising: providing a lightguide having a plurality of sections; and printing at least one telltalegraphic on a surface of said light guide, such that light passingthrough the light guide is scattered in all directions when the lightencounters the telltale graphic.
 10. The method of claim 9, furthercomprising inserting an opaque light guide insert into a receiving slotof said light guide, thereby dividing said light guide into a pluralityof sections.
 11. The method of claim 10, wherein printing at least onetelltale graphic on the surface of the light guide comprises printing atelltale graphic in at least two sections of said plurality of sections.12. The method of claim 9, wherein the light guide is provided as asingle piece light guide.
 13. The method of claim 9, further comprisingdisposing a dial adjacent a first surface of said light guide, whereinsaid dial comprises an opaque portion, and at least one translucentportion.
 14. The method of claim 13, wherein the at least one telltalegraphic is approximately the same color as the dial adjacent the lightguide.
 15. The method of claim 14, wherein the at least one telltalegraphic is a first shade of gray, and wherein the dial is a second shadeof gray distinct from the first shade of gray.